U.S. debt arithmetic calculator

Change an input to see the one-year debt effect and an illustrative path.

Inputs

One-year result

bt = 1 + i(1 + π)(1 + g)bt−1 − s

Next debt ratio (bt)

—

percent of GDP

Annual change

—

percentage points of GDP

What drives the change?

Interest less nominal growth
—
Primary deficit or surplus
—

Negative contributions reduce the debt ratio; positive contributions raise it.

30-year debt path

Fiscal years 2026–2056; selected inputs held fixed